1. Field of the Invention
The present invention relates generally to the field of vehicle gaskets, and more particularly to the field of gaskets used on the hubs of vehicles having floating drive axles.
2. Statement of the Problem.
Rear wheel drive vehicles typically have a differential housing, two axle housings, two axles that pass through the axle housings, two wheel hubs, and wheel bearings to support the axle housings on the wheel hubs. Each axle housing is hollow and attached to the differential housing. The axle housings and differential housing are typically a single unitary housing. Tires mounted on rims are conventionally attached to the wheel hubs. Many larger vehicles, such as three-quarter ton pickups and larger trucks, utilize floating axles. A floating axle is an axle that is removable from the hub. A lubricant is contained within the wheel hubs to lubricate the bearings. It is necessary during the life of a vehicle to service the rear wheel bearings, either to replace such bearings or merely to change the lubricant. Furthermore, it often becomes necessary to remove the wheel hub during the servicing of other portions of the vehicle, such as brakes, wheel seals, etc. Whenever a wheel hub is removed from its axle, the lubricant for the wheel bearings is lost and must be replaced. Refilling the wheel hub with lubricant for the wheel bearings is difficult.
The conventional method of supplying new lubricant to the wheel bearings is to reassemble the wheel hubs to the axles, and then to overfill the rear differential. The vehicle is then physically raised using a lifting device so as to incline the vehicle first toward one wheel and then toward the other wheel to encourage the lubricant to flow from the differential toward the wheel bearings through the axle housing. Obviously, having to lift each side of the vehicle adds to the steps and hence time necessary to complete any job requiring the removal of the wheel hub. Another conventional method is to, after overfilling the differential, move the vehicle to an incline. However, while this is easier than lifting the vehicle, moving the vehicle when the wheel bearings are without lubricant can damage the bearings.
Whether lifting or moving the vehicle to an incline, the lubricant, being rather thick, takes significant time to flow through the hollow axle housing into the wheel hub. Since the vehicle can not be operated until the wheel bearings are lubricated, valuable time is lost in lifting or moving the vehicle and then waiting for the lubricant to flow through the axle housings. This lost time adds to the labor costs (as mechanic's time is typically charged by the hour). Also, for commercial vehicles, this lost operating time has considerable value.
Furthermore, the conventional methods are inexact because estimating the correct amount by which to overfill the differential in order to obtain the desired amount of lubricant at the wheel bearings is difficult. Hence, in the current state of the art, the wheel bearings are often either under lubricated or over lubricated, neither condition being desirable. Therefore, it would be advantageous to have a means by which the wheel hub could be immediately reassembled without waiting for the lubricant to drain through the axle housings, and by which a precise amount of lubricant could be supplied directly to the wheel bearings.